Blastomonas aquatica sp. nov., a bacteriochlorophyll-containing bacterium isolated from lake water

Abstract

Yellow or orange-to-brown pigmented, ovoid or rod-shaped, Gram-negative staining, aerobic strains PE 4-5T and N5-10 m-1 were isolated from brackish water in Lake Peng Co and fresh to brackish water in Lake Namtso on the Tibetan Plateau, China. Bacteriochlorophyll a was produced by the isolates. The predominant cellular fatty acids were C16 : 1, C17 : 1 and C18 : 1 unsaturated fatty acids, C17 : 1ω6c (55.3 %), C17 : 1ω8c (13.0 %) and C18 : 1ω7c (10.4 %) for PE 4-5T and C18 : 1ω7c (54.7 %) and C16 : 1ω7c (18.0 %) for N5-10 m-1. The polar lipid profiles of strains PE 4-5T and N5-10 m-1 were composed of diphosphatidylglycerol, phosphatidylcholine (not detected in N5-10 m-1), phosphatidyldimethylethanolamine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, sphingoglycolipid and an unknown phospholipid. The predominant respiratory quinone was ubiquinone Q10 and the DNA G+C content was 66.0 mol% for both strains. The16S rRNA gene sequence of strain PE 4-5T shared 99.0 % similarity with that of N5-10 m-1, and 97.56 % similarity with those of Blastomonas natatoria LMG 17322T and Blastomonas ursincola DSM 9006T, respectively. The DNA–DNA hybridization relatedness between strains PE 4-5T and N5-10 m-1 was 79.0±1.0 %, but below 70 % with the type strains in the genus Blastomonas . Based on the variability of phylogenetic and phenotypic characteristics, the isolates should be classified as representatives of a novel species of the genus Blastomonas ; the name Blastomonas aquatica sp. nov. is proposed. The type strain is PE 4-5T ( = JCM 30179T = CGMCC 1.12851T).